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Degraded carrageenan (known as poligeenan molecular weight: 20 kDa to 30 kDa) causes ulcerative colitis in experimental animals. In this paper, the molecular weight distributions of 29 samples of food-grade refined carrageenans were studied by high performance liquid gel permeation chromatography (GPC) directly connected to vacuum-ultraviolet inductively coupled plasma-atomic emission spectrometry (ICP) (GPC/ICP) as well as GPC/refractive index (RI) detection. All samples of food-grade carrageenan had a major broad peak of high molecular weight which eluted at around 6.5 min in both RI and ICP mode (sulphur and carbon), and each sample of them had no obvious peak of poligeenan (the detection limit was about 5%). The number average molecular weights of these carrageenans ranged from 193 kDa to 324 kDa, and the weight average molecular weights ranged from 453 kDa to 652 kDa based on RI data. Some samples had a few minor peaks which eluted around 10-12 min. These peaks came from ionic sulphate, sucrose or glucose. It was considered that if the data-sampling programme was improved, the GPC/ICP system would become a more powerful technique for evaluation of carrageenan samples containing ionic substances and sugar.

Degraded carrageenan (known as poligeenan molecular weight: 20 kDa to 30 kDa) causes ulcerative colitis in experimental animals. In this paper, the molecular weight distributions of 29 samples of food-grade refined carrageenans were studied by high performance liquid gel permeation chromatography (GPC) directly connected to vacuum-ultraviolet inductively coupled plasma-atomic emission spectrometry (ICP) (GPC/ICP) as well as GPC/refractive index (RI) detection. All samples of food-grade carrageenan had a major broad peak of high molecular weight which eluted at around 6.5 min in both RI and ICP mode (sulphur and carbon), and each sample of them had no obvious peak of poligeenan (the detection limit was about 5%). The number average molecular weights of these carrageenans ranged from 193 kDa to 324 kDa, and the weight average molecular weights ranged from 453 kDa to 652 kDa based on RI data. Some samples had a few minor peaks which eluted around 10-12 min. These peaks came from ionic sulphate, sucrose or glucose. It was considered that if the data-sampling programme was improved, the GPC/ICP system would become a more powerful technique for evaluation of carrageenan samples containing ionic substances and sugar.

-This study was designed to evaluate any adverse effect of fermentation-derived cellulose, produced by Acetobacter aceti subspecies xylinum, when administered to both sexes of F344 rats at dietary levels of 0, 1.25, 2.5, and 5.0% for 28 days. The treatment had no adverse effects on clinical signs, mortality, body weights and food and water consumption, or on urinalysis, ophthalmology, hematology, blood biochemistry, and histopathology findings. At necropsy, slight increased absolute and relative cecum weights, evident in females ingesting 2.5% and 5.0% dietary levels, were considered to be a physiological adaptation to the poorly absorbed fermentation-derived cellulose. The non-observed-adverseeffect level (NOAEL) from the present study was concluded to be 5.0% in the diet (5,331 mg/kg body weights/day for males, and 5,230 mg/kg body weights/day for females).Key words: Fermentation-derived cellulose, Food additive, Subacute toxicity, F344 rats Correspondence: Akihiro Hagiwara (E-mail: hagiwara@dims.co.jp) Original ArticleThe Journal of Toxicological Sciences (J. Toxicol. Sci.) Vol.35, No.3, 317-325, 2010 Vol. 35 No. 3 317 MATERIALS AND METHODSThe present study was conducted in compliance with the Good Laboratory Practice (GLP) Standards of the Japanese Ministry of Health and Welfare Ordinance No. 21 (March 26th, 1997) and in accordance with the "Guidelines for Designation of Food Additives and for Revision of Standards for Use of Food Additives" of the Japanese Ministry of Health and Welfare (Eika No. 29, March 22nd, 1996). The animals were given fermentation-derived cellulose at dietary levels of 0% (the control), 1.25%, 2.5% and 5.0% for 28 days. The selection of the highest dose was based on the maximum dietary level conforming to the above-mentioned Guideline, and lower levels were set at 2.5% and 1.25% with a proportionality factor of 2. Test materialThe fermentation-derived cellulose used in the present study was supplied by San-Ei Gen F.F.I. Inc., with specifications as follows: label name, fermented cellulose; Lot No., 98-452P; 60% in purity, mixed with 20% sodium carboxymethylcellulose, and 20% sucrose; milky white powder; storage condition, at room temperature. The primary structure of fermentation-derived cellulose is illustrated in Fig. 1 (Omoto et al., 2000). Diet preparation and analysisThe test material, fermentation-derived cellulose, was incorporated at the required levels into Labo MR stock powdered diet (Nihon Nosan Kogyo, K.K., Tokyo, Japan) and mixed with a blender, model KS101 (Shin Kantou Inc., Tokyo, Japan) for about 30 min. Treatment diets were put in sterile cans and stored at room temperature. Diet preparation was carried out only once, prior to the start of the experiment. Stability and concentration analysis of test material in the prepared diets could not be performed, since analytical methods have yet to be established. As cellulose is a major constituent of many foods of plant origin, and quite inert material, fermentation-derived cellulose in the prepared diet migh...